Chord of Calling RAV/156

Set: Ravnica: City of Guilds
Collector Code: RAV/156
Name: Chord of Calling
Type: Instant
Oracle text: Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.
Rarity: Rare